How to calculate the mode in ArangoDB?

Question

I have transactions like this

{"cust_id": "593ec", "recorded": "2015-10-15T11:22:22", "account_id": 1, "account_status": "P"},
{"cust_id": "593ec", "recorded": "2016-03-06T02:00:11", "account_id": 2, "account_status": "A"}, ...

I want to summarize how many unique customers and for each customer how many unique accounts that customer has and the mode value for account status by frequencies?

Expected Result:

[
   {"cust_id": "593ec", "accounts": 11, "status_q1": "A", "status_q2": "N"},
   {"cust_id": "114sd", "accounts": 0,  "status_q1": "P", "status_q2": "P"},
   .....
]

Thank you

Answer 1

You can use COLLECT to group the documents by cust_id .

Under the assumption that your collection with the transactions is named transactions ,

this query:

FOR t IN transactions
  COLLECT c = t.cust_id INTO status = t.account_status
  RETURN {cust_id: c, accounts : LENGTH(status), status}

give you the following result:

[
  {"cust_id": "593ec", "accounts": 2, "status": ["P","A"]},
  ...
]